求1到5階乘之和

方法一：
s = 1
sum = 0
for i in range(1,6):
    s = s*i
    sum += s
print(s)
print(sum)

方法二：效率低，每次都要重新算k

n = 0 
for i in range(1,6):
    k = 1
    for j in range(1, i + 1):
        k = k * j
    n = n + k
print(n)